1. Field of the Invention
This invention relates to a high density pneumatic transport system for use in solid materials with which solid materials continuously supplied from a tablet molding machine are transported through a transport pipe into a collector by the use of pressurized gas. Herein solid materials denote solids having regular shape regardless of figure and size of the grain thereof a such as medical tablets and confectionery.
2. Prior Art
U.S. Pat. Nos. 4,856,941 and 4,904,128 disclose a system to execute a method in which powdered or granular materials including solids such as medical tablets can be pneumatically transported in a transport pipe.
In U.S. Pat. No. 4,856,941, when powdered or granular materials stored in an airtight transport tank are taken out to a transport pipe, a transport plug of particular shape is inserted to section the materials and the plug transports the sectioned materials through the pipe at a low speed. In U.S. Pat. No. 4,904,128, a transport pipe is constructed with a plurality of reducers and powdered or granular materials taken out from an airtight transport tank are transported at high density in a lower section and a vertical section of pipe and at a low speed in the form of a long column in the upper horizontal section of pipe without using a transport plug. Both inventions represent new and ideal proposals in which powdered or granular materials can be transported at high density and at a low speed in a transport pipe without causing any chips or cracks.
However, in U.S. Pat. No. 4,856,941, a problem exists with controlling operations in which a transport plug is to be inserted prior to intermittent supply of pressurized transport gas and the inserted plug is to be removed after completing transportation of powdered or granular materials. Also in U.S. Pat. No. 4,904,128, a large capacity airtight transport tank is required for storing powdered or granular materials to be transported, resulting in a large overall. There have also been problems in that the supply pressure of pressurized transport gas has to be sensitively adjusted and moreover the adjustment of the transport gas pressure when the transferring of materials starts has also been troublesome.
These systems requires a large airtight transport tank and have a batch transportation method applied in which powdered or granular materials stored in the airtight transport tank can be continuously supplied into the transport pipe until the tank becomes empty, the transportation of materials is stopped while the tank is empty and the transportation is started again after materials are supplied and stored in the tank. When the transportation of materials is stopped halfway, a blowout phenomenon occurs because of blowing of pressurized gas accumulated in the tank. Solutions for such a blowout problem have been desired.